The disclosure relates to a valve of an accumulator device, which is formed by means of an accumulator cylinder and an accumulator piston guided therein. The valve comprises a valve sealing body for selective opening and closure of a valve opening at a valve seat and having an opening means for selectively raising the valve sealing body from the valve seat, which opening means is held by means of a spring element. The disclosure furthermore relates to the use of a valve of this kind in an accumulator device, in particular for a hydraulic unit of a vehicle brake system.
Accumulator devices of the type in question are used particularly in vehicle brake systems and serve to provide temporary storage for pressure medium in the form of brake fluid. In this case, the pressure medium is returned from wheel brake cylinders or fed in from a main accumulator of the vehicle brake system, e.g. in vehicle brake systems with an antilock brake system (ABS) and an electronic stability program (ESP).
Valves in accumulator devices of hydraulic units, in particular of vehicle brake systems, are used to control the quantity of pressure medium within the associated accumulator device.
The accumulator devices comprise an accumulator cylinder and an accumulator piston which is guided therein and by means of which an accumulator volume for the pressure medium is delimited. The pressure medium can be delivered from the accumulator volume into a brake circuit when required. If the accumulator volume decreases, the accumulator piston travels into the accumulator cylinder to a depth such that, by means of an opening means, it opens a valve closed in a spring-assisted manner. Pressure medium then flows into the accumulator cylinder again through the opened valve.
Conventionally employed opening means are configured as a pin which is inserted, in particular press-fitted, in an accurately fitting manner at a fixed location in the accumulator piston. Manufacture with an accurate fit is necessary since the opening means must strike the valve sealing body correctly in order to raise it. In general, the pin-shaped opening means is passed through the valve opening to the valve sealing body from the piston side. For this purpose, high precision in the component geometry and in the stroke motion of the accumulator piston is necessary. Precise component geometry can be achieved only by very dimensionally accurate and hence expensive components, manufacture and assembly. A precise stroke motion entails a complex configuration with, for example, additional guide rings and a long length of guidance for the accumulator piston.